Preconfiguring
Physical Interfaces

This module describes the preconfiguration of physical
interfaces on the
Cisco ASR 9000 Series
Aggregation Services Routers.

Preconfiguration is supported for the following types of
interfaces and controllers:

Gigabit Ethernet

10-Gigabit Ethernet

Management Ethernet

Packet-over-SONET/SDH (POS)

Serial

SONET controllers and channelized SONET controllers

Preconfiguration allows you to configure modular services cards
before they are inserted into the router. When the cards are inserted, they are
instantly configured.

The preconfiguration information is created in a different
system database tree (known as the
preconfiguration directory on the route
switch
processor [RSP]), rather than with the regularly configured interfaces.

There may be some preconfiguration data that cannot be verified
unless the modular services card is present, because the verifiers themselves
run only on the modular services card. Such preconfiguration data is verified
when the modular services card is inserted and the verifiers are initiated. A
configuration is rejected if errors are found when the configuration is copied
from the preconfiguration area to the active area.

Note

Ten GigE interfaces
will not show egress statistics when loopback line is configured because the
loopback is closed at the interface controller level, before the Network
Processor (NP). But on One GigE interfaces the line loopback is closed in the
NP.

Preconfiguring
Physical Interfaces

This module describes the preconfiguration of physical
interfaces on the
Cisco ASR 9000 Series
Aggregation Services Routers.

Preconfiguration is supported for the following types of
interfaces and controllers:

Gigabit Ethernet

10-Gigabit Ethernet

Management Ethernet

Packet-over-SONET/SDH (POS)

Serial

SONET controllers and channelized SONET controllers

Preconfiguration allows you to configure modular services cards
before they are inserted into the router. When the cards are inserted, they are
instantly configured.

The preconfiguration information is created in a different
system database tree (known as the
preconfiguration directory on the route
switch
processor [RSP]), rather than with the regularly configured interfaces.

There may be some preconfiguration data that cannot be verified
unless the modular services card is present, because the verifiers themselves
run only on the modular services card. Such preconfiguration data is verified
when the modular services card is inserted and the verifiers are initiated. A
configuration is rejected if errors are found when the configuration is copied
from the preconfiguration area to the active area.

Note

Ten GigE interfaces
will not show egress statistics when loopback line is configured because the
loopback is closed at the interface controller level, before the Network
Processor (NP). But on One GigE interfaces the line loopback is closed in the
NP.

Note

Only physical interfaces can be preconfigured.

Feature History
for Preconfiguring Physical Interfaces

Release

Modification

Release 3.7.2

Ethernet interface preconfiguration was introduced.

Release 4.0.0

POS interface preconfiguration was introduced.

Prerequisites for Preconfiguring Physical Interfaces

You must be in a user group associated with a task
group that includes the proper task IDs. The command reference guides include
the task IDs required for each command. If you suspect user group assignment is
preventing you from using a command, contact your AAA administrator for
assistance.

Before preconfiguring physical interfaces, be sure
that the following condition is met:

Preconfiguration drivers and files are
installed. Although it may be possible to preconfigure physical interfaces
without a preconfiguration driver installed, the preconfiguration files are
required to set the interface definition file on the router that supplies the
strings for valid interface names.

Information About Preconfiguring Physical Interfaces

To preconfigure interfaces, you must understand the following concepts:

Physical Interface Preconfiguration Overview

Preconfiguration is the process of configuring interfaces before they are present in the system. Preconfigured interfaces are not verified or applied until the actual interface with the matching location (rack/slot/module) is inserted into the router. When the anticipated modular services card is inserted and the interfaces are created, the precreated configuration information is verified and, if successful, immediately applied to the router’s running configuration.

Note

When you plug the anticipated modular services card in, make sure to verify any preconfiguration with the appropriate show commands.

Use the show run command to see interfaces that are in the preconfigured state.

Note

We recommend filling out preconfiguration information in your site planning guide, so that you can compare that anticipated configuration with the actual preconfigured interfaces when that card is installed and the interfaces are up.

Tip

Tip Use the commit best-effort command to save the preconfiguration to the running configuration file. The commit best-effort command merges the target configuration with the running configuration and commits only valid configuration (best effort). Some configuration might fail due to semantic errors, but the valid configuration still comes up.

Benefits of Interface Preconfiguration

Preconfigurations reduce downtime when you add new cards to the system. With preconfiguration, the new modular services card can be instantly configured and actively running during modular services card bootup.

Another advantage of performing a preconfiguration is that during a card replacement, when the modular services card is removed, you can still see the previous configuration and make modifications.

Use of the Interface Preconfigure Command

Interfaces that are not yet present in the system
can be preconfigured with the
interface preconfigure command in global
configuration mode.

The
interface preconfigure command places the router
in interface configuration mode. Users should be able to add any possible
interface commands. The verifiers registered for the preconfigured interfaces
verify the configuration. The preconfiguration is complete when the user enters
the
end command, or any matching exit or global
configuration mode command.

Note

It is possible that some configurations cannot
be verified until the modular services card is inserted.

Do not enter the
no shutdown command for
new preconfigured interfaces, because the no form of this command removes the
existing configuration, and there is no existing configuration.

Users are expected to provide names during
preconfiguration that will match the name of the interface that will be
created. If the interface names do not match, the preconfiguration cannot be
applied when the interface is created. The interface names must begin with the
interface type that is supported by the router and for which drivers have been
installed. However, the slot, port, subinterface number, and channel interface
number information cannot be validated.

Note

Specifying an interface name that already exists
and is configured (or an abbreviated name like e0/3/0/0) is not permitted.

Active and Standby RSPs and Virtual Interface Configuration

The standby RSP is available and in a state in which it can take over the work from the active RSP should that prove necessary. Conditions that necessitate the standby RSP to become the active RSP and assume the active RSP’s duties include:

Failure detection by a watchdog

Standby RSP is administratively commanded to take over

Removal of the active RSP from the chassis

If a second RSP is not present in the chassis while the first is in operation, a second RSP may be inserted and will automatically become the standby RSP. The standby RSP may also be removed from the chassis with no effect on the system other than loss of RSP redundancy.

After failover, the virtual interfaces will all be present on the standby (now active) RSP. Their state and configuration will be unchanged, and there will have been no loss of forwarding (in the case of tunnels) over the interfaces during the failover. The Cisco ASR 9000 Series Router uses nonstop forwarding (NSF) over tunnels through the failover of the host RSP.

Note

The user does not need to configure anything to guarantee that the standby interface configurations are maintained.

How to Preconfigure Physical Interfaces

This task describes only the most basic
preconfiguration of an interface.

SUMMARY STEPS

1.configure

2.interface
preconfigure
type
interface-path-id

3.Use one of the following commands:

ipv4
addressip-address subnet-mask

ipv4
addressip-address/prefix

4.Configure additional interface parameters, as described in this
manual in the configuration chapter that applies to the type of interface that
you are configuring.

Enters interface preconfiguration mode for
an interface, where
type
specifies the supported interface type that you
want to configure and
interface-path-id
specifies the location where the interface will be
located in
rack/slot/module/port
notation.

Step 3

Use one of the following commands:

ipv4
addressip-address subnet-mask

ipv4
addressip-address/prefix

Example:

RP/0//CPU0:router(config-if-pre)# ipv4 address 192.168.1.2/32

Assigns an IP address and mask to the interface.

Step 4

Configure additional interface parameters, as described in this
manual in the configuration chapter that applies to the type of interface that
you are configuring.

Step 5

end or
commit
best-effort

Example:

RP/0//CPU0:router(config-if-pre)# end

or

RP/0//CPU0:router(config-if-pre)# commit

Saves configuration changes.

When you issue the
end command, the system prompts you
to commit changes: Uncommitted changes found, commit them before
exiting (yes/no/cancel)?

Entering
no exits the configuration session and
returns the router to EXEC mode without committing the configuration changes.

Entering
cancel leaves the router in the current
configuration session without exiting or committing the configuration changes.

Use the
commit best-effort command to save
the configuration changes to the running configuration file and remain within
the configuration session. The
commit best-effort command merges the
target configuration with the running configuration and commits only valid
changes (best effort). Some configuration changes might fail due to semantic
errors.

Step 6

show
running-config

Example:

RP/0//CPU0:router# show running-config

(Optional) Displays the configuration
information currently running on the router.